The present invention relates to a laser apparatus employing a semiconductor laser or the like, and a method of controlling the laser apparatus. More particularly, the present invention relates to a laser apparatus capable of controlling and driving a temperature control unit on the basis of the total power consumption of the temperature control unit and a driving means so that the laser apparatus operates at a minimum power consumption.
Laser oscillators employing a semiconductor laser have been used in various fields. Laser technology has made remarkable advancement in recent years and battery-powered outdoor laser oscillators, such as survey instruments, are applied to various fields as well as laser oscillators which use a commercial power supply. However, conventional laser oscillators consume much power, and hence the batteries of conventional battery-powered oscillators are exhausted in a relatively short operating time.
Therefore, there has been an intense demand for the development of a laser apparatus capable of emitting a laser beam at a high efficiency, of operating at a low power consumption rate and of continuously operating for a greatly extended operating time.
A laser emits a laser beam at a maximum efficiency when the peak of the gain curve of the laser coincides with the position of the longitudinal mode. Even if an optical resonator is adjusted to a most efficient condition during the assembly of the same the optical resonator changes with time to an inefficient condition due to aged deterioration.
The refractive index of a nonlinear optical medium varies with temperature and hence the quantity of output light varies with the ambient temperature.